the word 'turnabout' is a transparent english compound formed from two native elements. the verb 'turn', with its origins in latin via old english, carries the core sense of rotation or change in direction. when combined with the adverbial particle 'about', which implies a reversal or a complete circuit, the compound literally means 'to turn so as to face the opposite way'. this literal sense of physical reversal evolved naturally into the modern abstract meaning denoting a complete reversal in opinion, policy, or fortune. the secondary meaning referring to a revolving platform, such as a merry-go-round, retains the original, more concrete sense of rotational movement.

Structure: turn + about turn (from old english turnian/tyrnan, from latin tornare 'to turn on a lathe', functional role: verb root meaning to rotate or change direction). about (from old english abūtan, from on 'on' + būtan 'outside of', functional role: adverbial particle indicating reversal or surrounding action).